South Americans hit by dengue fever epidemicThe mosquito-borne dengue fever virus has sickened hundreds of thousands in South America -- the largest such epidemic in years.May 17, 2009 - Miami Herald

BY JOHN ENDERS, Special to The Miami Herald

SANTA CRUZ, Bolivia -- While the world continues to be on alert for a potential swine flu pandemic, South Americans have been suffering for months from one of the worst viral epidemics on record.

Hundreds of thousands of people have been sickened by dengue fever this year; more than 70 have died.

''This is the largest epidemic in many years,'' said Dr. Eddy Martinez, the director of epidemiology for Bolivia's Ministry of Health in the capital city of La Paz.

By mid-April, he said, there had been more than 55,000 suspected cases in Bolivia's eastern and southern lowlands, with 25 fatalities. Most of those were in Santa Cruz in eastern Bolivia.

Dengue, a mosquito-borne virus endemic in lowland tropical regions around the world but little known in the northern hemisphere, struck particularly hard this year in Bolivia, Paraguay, Argentina and Brazil.

Health officials say the disease is increasingly a problem in the region's densely-populated cities, and is spreading.

At the San Juan de Dios hospital here, where most dengue victims come, doctors treated about 100 people a day during the peak of the recent outbreak in February and March, according to Dr. Gonzalo Rocabado, an internist. They arrived by taxi and busload all summer long -- mothers, fathers, children and grandparents, all with one thing in common: flu-like symptoms.

The epidemic in Bolivia has eased in recent weeks as the weather has grown colder, but it continues in areas that are warmer.

There are four specific serotypes of the dengue virus. A person who recovers from one strain becomes immune to that strain only, and, experts say, is likely to be more susceptible to the others.

The most frightening form of the disease is dengue hemorrhagic fever, which affects the circulatory system and internal organs. Those suffering from advanced hemorrhagic dengue bleed from their noses and ears, and internally. Organ failure can lead to death.

The World Health Organization calls dengue ''a major international health concern.'' It recently noted that 2.5 billion people live in lowland and tropical areas where dengue viruses can be transmitted, and that the spread of both the mosquito vectors and the viruses has led to the global resurgence of dengue in the past 25 years.

This year, dengue has been a critical problem in South America.

Almost 150,000 cases have been detected in Brazil, 4,000 cases in Paraguay, 13,000 in Argentina and more than 55,000 in Bolivia. According to official statistics reported by the Pan American Health Organization, there were a quarter million cases of dengue in Latin America and the Caribbean through late April, and 74 deaths. A third of the deaths were in Bolivia.

In 2008, more than one million cases of dengue were reported in Latin America and the Caribbean, with 554 deaths, according to the Pan American Health Organization.

There are no anti-viral drugs for dengue. Doctors must treat the symptoms, mostly dehydration and severe fever.

During the southern summer, just ending, medical providers in Bolivia, Brazil and northern Argentina were overwhelmed.

International health officials are now concerned that the coming rainy season in the Caribbean may lead to further outbreaks in countries in that region.

Many of those arriving at the San Juan de Dios hospital are poor. They must pay to enter the hospital, and they usually must pay for their own saline solutions, painkillers and other medicines.

Experts say the biggest cause of the upsurge in dengue in urban areas is the reproduction of mosquitoes in standing water. A daylong campaign in Santa Cruz in March had sanitation, civic and health workers going door to door throughout this city of 1.5 million in an attempt to get people to rid their properties of water-bearing receptacles where mosquitoes thrive.

In Argentina, health officials say the worst affected areas are those in the north, neighboring Bolivia and Paraguay, but cases were reported in the Buenos Aires metropolitan area as well.

According to the CDC, four factors encourage the disease's spread: increased urbanization, failed public health infrastructures in many countries, increased travel by airplane, and a lack of effective mosquito control.

These factors, along with global climate change, ''can only aggravate the situation,'' said Dr. Mirta Roses, the director of the Pan American Health Organization, based in Washington. Higher spending by governments at all levels on clean water, refuse disposal, vector control and accessible public health services are required if dengue is to be contained.